This species is known only from Puerto del Gallo, in the Sierra Madre del Sur de Guerrero, north-east of Atoyac de Alvarez, central Guerrero, Mexico, at 2,800-3,000m asl.
Habitat and Ecology
The species is terrestrial and inhabits pine-fir and pine-oak-fir forests, and is usually found under logs or under the bark of fallen rotting logs. It can live in somewhat degraded forest. It reproduces by direct development.
Recent observations show that the species still exists.
The main threat is habitat loss as a result of logging and expanding agriculture.
It has not been found in any protected areas, and there is an urgent need for forest protection along the Milpillas-Atoyac transect.
Red List Status
Listed as Endangered because its Extent of Occurrence is less than 5,000 km2, all individuals are in fewer than five locations, and there is continuing decline in the extent and quality of its habitat in central Guerrero, Mexico.
Gabriela Parra-Olea, David Wake 2008. Thorius grandis. The IUCN Red List of Threatened Species 2008: e.T59411A11933425. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T59411A11933425.en